Google's annual developer conference is normally a relentlessly positive cheerleading session to excite developers to create products for the company and its Android operating system. But this year, there was a hint of a more serious tone as the company discussed creating technology that is not simply innovative, but responsible.

The theme of the company's annual conference was "Make Good Things Together". Google chief executive Sundar Pichai said in a keynote address to about 7000 developers and journalists that Google wants to push ahead to innovate, but he acknowledged that the tech giant can't be "wide-eyed" about it.